port(?Address)

Port to bind to. Address is either a port or a term Host:Port. The port may be a variable, causing the system to select a free port. See tcp_bind/2.

tcp_socket(+Socket)

If provided, use this socket instead of the creating one and binding it to an address. The socket must be bound to an address.

workers(+Count)

Determine the number of worker threads. Default is 5. This is fine for small scale usage. Public servers typically need a higher number.

timeout(+Seconds)

Max time of inactivity trying to read the request after a connection has been opened. Default is 60 seconds. See set_stream/1 using the timeout option.

keep_alive_timeout(+Seconds)

Time to keep `Keep alive' connections alive. Default is 2 seconds.

local(+Kbytes)

global(+Kbytes)

trail(+Kbytes)

Stack sizes to use for the workers. The default is inherited from the main thread. As of version 5.9 stacks are no longer pre-allocated and the given sizes only act as a limit. If you need to control resource usage look at the spawn option of http_handler/3 and library(thread_pool).

A typical initialization for an HTTP server that uses http_dispatch/1 to relay requests to predicates is:

:- use_module(library(http/thread_httpd)).
:- use_module(library(http/http_dispatch)).

start_server(Port) :-
    http_server(http_dispatch, [port(Port)]).

Note that multiple servers can coexist in the same Prolog process. A notable application of this is to have both an HTTP and HTTPS server, where the HTTP server redirects to the HTTPS server for handling sensitive requests.